LCA Poly Bushing Failure - what to do now?

[66 Sat]

Yes, I've got the shafts with the grease fitting. The spare bushings I had came with their own grease which I have spread liberally inside and out, and yes it's very sticky. It's called Prothane Super Grease and is white.
I've got the first side back together, just final re-assembly.
Home made press to get the bushing and shaft into the socket.

 

[wwheel]

69_Coronet makes an excellent point. I molded urethane for decades and using the proper grease is critical. Certain urethanes are compatible with mineral grease but I suspect this type of urethane is NOT. As stated, the white sticky grease is silicone based is what you want to use for these urethane bushes.

When the urethane is exposed to an incompatible material, it will slowly turn to a consistency of cheese. How long depends on other factors, but 5 to 10 years sounds about right. I have seen it many times and is quite dramatic when it is uncovered. This sounds like a compatibility issue. What grease was used?

 

[Moparfever65]

PST has a lifetime warranty.

View attachment 1611368

I find warranties on parts that are cheap for the manufacturer to replace pretty worthless. Now if they covered the labor to replace it, that would be standing behind your product!

 

[dadsbee]

This might be a silly question but- any chance the LCA nuts were tightened before the height and weight was set? It's the only thing the FSM notes to do when setting up LCA's.

Doesn't matter with a Poly bushing, they're not bonded to any pressed in shell.

That said.... go back to stock rubber and let 2 generations down the road worry about it the next time!

 

[66 Sat]

69_Coronet makes an excellent point. I molded urethane for decades and using the proper grease is critical. Certain urethanes are compatible with mineral grease but I suspect this type of urethane is NOT. As stated, the white sticky grease is silicone based is what you want to use for these urethane bushes.

When the urethane is exposed to an incompatible material, it will slowly turn to a consistency of cheese. How long depends on other factors, but 5 to 10 years sounds about right. I have seen it many times and is quite dramatic when it is uncovered. This sounds like a compatibility issue. What grease was used?

Not sure what I used back then but I don't recall it being white and sticky.
I know I have re-greased them with the blue lithium grease , so your theory sounds correct.
I'm using the right stuff now, small Prothane tubes were in the packet with the bushings.
Driver's side is complete. Just need my lower back to stop hurting and I'll get into the passenger side.

 

[Speedbird]

If you can get this down there use it on everything.
It's high pressure, high temp and water proof.
It is also compatible with all other greases so using it in prior applications will not be a problem.
You will actually save money buying only one type of grease.
Valvoline makes a green synthetic but red is the most used by me in past aircraft application. (Mcdonald Douglas)
Green was what we used on Boeing.
Unless it was brakes which was black due to Moly I guess.

 

[Mojoe9955]

Go to BAC for new delrin bushings and pivots. I went with them after my new Made in US Moog lower control arm bushings gave way on the road...can you say WTF

 

[padam]

BAC?

 

[Kern Dog]

Go with rubber and it will last the rest of your life and be quieter.
Mike

I agree in part.
Last the rest of your life? The original rubber bushings don't last a lifetime and the new ones aren't made as well so no, I don't believe any rubber bushing is going to last a lifetime. It isn't just wear and road use that degrades them, it is time and environment. I had to replace Moog bushings after less than 10,000 miles even though I had bigger torsion bars that, in theory, prevented the suspension from wild swings in the range of travel.

 

[Mojoe9955]

BAC?

 

[Mojoe9955]

Bergman Auto Craft

 

[Tony Tee]

I machined my own lca bushings out of chromoly steel with 3 inner rotating sleeves and drilled the shafts for a grease fitting and added a seal. I know they will be noisy but I work with urethane at my job, and I'll use urethane on end links and

sway bars and bump stops. but that's about it. And rubber is a better choice if it's not real old or not made in China. Anyway this is my experiment. I jut don't know when I will test them in my charger.

 

[66 Sat]

Well I finished the other side earlier this week and road tested the car a few times, then took it on a decent 100 mile run to the city yesterday

- all is well. Hopefully with the correct grease these poly bushings will last a lot longer.

It took me probably 5 hours to do the driver's side, including having to jack the engine up a touch for the LCA to clear the headers, getting all the tools out etc.

The passenger side took about 3 hours which was pretty good going. I'm not saying it's a job I want to do again, but at least I know I can get them done myself fairly quickly.

 

[John Keyburn]

Bergman Auto Craft

Mojoe, Can you describe how the derlin bushings get installed. I cant seem to find anything. I just ordered the BAC Derlin bushings with the center pins. Are the center pins the same as the old pins? In other words could I reuse the old pins after removing the inner sleeve?

 

[Bighouse]

I have a set of Moog lower bushing sitting on my chargers fender right now. They say made in India. I’m contemplating what to do.

Just replying to myself here…

I did my lower bushings and used these Moogs. Everything pressed together real nice and tight. No issues. Back together and going down the road just fine.

Just thought I’d let you all know they’re ok

 

[A12 Wanna Bee]

Mojoe, Can you describe how the derlin bushings get installed. I cant seem to find anything. I just ordered the BAC Derlin bushings with the center pins. Are the center pins the same as the old pins? In other words could I reuse the old pins after removing the inner sleeve?

John,

Regarding the install of the BAC Delrin LCA bushings:

Installation tips:

Remove rubber bushing outer shell from control arm

Insert the delrin bushing 25% of the way.

Lube the pin surface that contacts the ID of the new bushing.

Insert the pin 25% into the bushing.

Lightly press together. Pin pushes all the way to the stop.

Regarding the pivot pins, I believe the BAC pins are .94 but my OEM pins still have the inner metal part of the bushing attached. They measure .945 with the inner bushing attached. I’ll try to pull it off this afternoon and get you a good measurement. I am hardly the authority on any of this. Just a guy in his garage with a cheap set of calipers.
I’d call Peter @ BAC and get it straight from the horses mouth if I were you. Personally, I bought both my pins and the Delrin bushings from BAC as a package. Peter machines his pins to precisely fit his bushings.

 

[1STMP]

Go to BAC for new delrin bushings and pivots. I went with them after my new Made in US Moog lower control arm bushings gave way on the road...can you say WTF

Delrin requires a much
tighter tolerance for
alignment than you'll
find on any OEM application.
There's little give in the
material and it's prone to
failure if the tighter
tolerances are ignored.
Plus a harsher ride and
a noticeable increase in
vibration. Great for track
use, terrible for the street.

 

[493 Mike]

I agree in part.
Last the rest of your life? The original rubber bushings don't last a lifetime and the new ones aren't made as well so no, I don't believe any rubber bushing is going to last a lifetime. It isn't just wear and road use that degrades them, it is time and environment. I had to replace Moog bushings after less than 10,000 miles even though I had bigger torsion bars that, in theory, prevented the suspension from wild swings in the range of travel.

Sorry. I was using my age for a baseline (74)!
Mike